Police is available as a marvelous, 2-disc special edition in France from G.C.T.H.V. (that's Gaumont Columbia Tristar Home Video to you). Disc one features a beautiful anamorphic print of the film (in its original 1.66:1), "presented" (which means, I suppose, a video introduction) by Catherine Breillat. Then, on disc two, there's an interview with Breillat, a 35 minute documentary, deleted scenes, a featurette and some other stuff. What it does not feature, however, are English subtitles.
This is also available in the first volume (there's a volume 2 with other films) of a Maurice Pialat boxed set - it's 9 discs all told, including both discs of Police, which are the same as the ones sold separately.
There is no US DVD (or UK, or from anywhere else) so we English speakers are left to make do with the old, fullscreen VHS that was released by New Yorker video back in the 90's.